The packaging of integrated circuit (IC) chips is one important step in the manufacturing process. The packaging of an IC chip has two main purposes: to protect delicate semiconductor chips, and to connect interior integrated circuits to exterior connections. As semiconductor devices reach higher levels of integration, especially for 3D IC technology, packaging of an IC chip accounts for a considerable portion of the cost of producing the device, and failure of the package leads to costly yield reduction.
Several packaging technologies are available. For example, a wire bonding technology uses upward-facing chips with wires connected to each pad on the chip. In flip chip technology, a flip chip microelectronic assembly includes a direct electrical connection of a downward-facing (that is “flipped”) chip onto an interposer or a substrate, using solder bumps as interconnects. The use of flip chip packaging has dramatically grown as a result of the advantages in size, performance, flexibility, reliability, and cost over other packaging methods.